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VAGILITY IN AN EPHEMERAL HABITAT SPECIALIST EXPLAINS PANMIXIA: A RECENT RANGE EXPANSION AND RETRACTION DO NOT
Amie E Settlecowski1,2, Brant C Faircloth3,4, Jeremy M Brown3,4
1School of Renewable Natural Resources, Louisiana State University and Agricultural Center, Baton Rouge, LA, USA.
The Journal of Heredity
|August 6, 2026
Summary
Bachman's Sparrow (Peucaea aestivalis) exhibits panmixia due to high vagility, not recent range shifts. Habitat loss is increasing genetic structure, potentially limiting gene flow for this ephemeral habitat specialist.
Area of Science:
- Ecology
- Evolutionary Biology
- Conservation Genetics
Background:
- Ephemeral habitats can promote high vagility and gene flow.
- Habitat alterations may increase connectivity and reduce genetic diversity at colonization fronts.
Purpose of the Study:
- To investigate the genetic structure of Bachman's Sparrow (Peucaea aestivalis) in relation to its use of ephemeral habitats.
- To determine if panmixia is a characteristic of this species or a result of recent range changes.
Main Methods:
- Analysis of historical and modern single nucleotide polymorphism (SNP) data spanning over 150 years.
- Comparison of genetic diversity across different regions, including extralimital areas.
Main Results:
- Bachman's Sparrow demonstrates panmixia, consistent with its ephemeral habitat specialization.
- High vagility has mitigated expected genetic signatures at colonization fronts.
- Recent habitat loss and fragmentation are causing small but significant increases in genetic structure.
Conclusions:
- Limited genetic structure is characteristic of Bachman's Sparrow, supporting the role of high vagility in locating transient habitats.
- Habitat fragmentation is beginning to impact genetic variation, highlighting potential dispersal barriers.
- Findings suggest implications for understanding gene flow limitations in other long-distance dispersing species.
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